Steam generator



y 1951 e. NEHRBAS 2,554,631

STEAM GENERATOR Filed Feb. 20, 1947 2 Sheets-Sheet 1 HOW/9RD G.NEHRBfl-S' IN YEN TOR.

43 40 43 a BY W W May 29, 1951 H. G. NEHRBAS STEAM GENERATOR Filed Feb.20, 1947 xxx A v 2 Sheets-Sheet 2 Mbu l I I 30 3/ 32 33 Y Haw/m1: G.NEH/PEAS IN VEN ro/R By M W Patented May 29, 1951 UNITED I STATES OFFICESTEAM GENERATOR Howard G. Nehrbas, Hammond, Ind, assignor to CombustionEngincering-Superheater, Inc., a corporation of Delaware ApplicationFebruary 20, 1947, Serial No. 729,761

6 Claims.

The present invention relates to heat transfer apparatus andparticularly to improvements in a forced circulation steam generator ofhigh capacity.

The present invention contemplates the prothe ends of the inner wall ofthe furnace or vision of a steam generator of high capacityapproximately in the plane marking the diviwhich is nevertheless ofsimple and compact sion between the furnace chamber I0 and theconstruction, adapting it for use in situations convection passage ll.As appears in Figure 3 where there is only a limited amount of spacethese headers are of inverted L-shape and the to accommodate such agenerator as when ap ends I6, I? of the furnace coils l3, l4 and I5plied to a Diesel unit for supplying steam to are connected to thevertically extending legs heat the cars of a train. A further feature of28, 2| of these inverted L-shaped supply and the invention is aconstruction affording ready collecting headers. access to the steamgenerating elements for in- To provide an opening for the flow of gasesspecting them or replacing them if necessary. from the furnace Ill intothe convection pas- The invention will be best understood upon sage Hsome of the tubes 23 of the lowermost consideration of, the followingdetailed descripradiant coil 13 are staggered or offset horizontion ofan illustrative embodiment thereof tally with respect to the adjacenttube porwhen read in conjunction with the appended tions 2 3 so as toleave gas fiOW Op 5 drawing in which; between a number of adjacent tubesin the in- Figure 1 is a longitudinal sectional view of a ner wall ofthe furnace which otherwise is sursteam generator constructed inaccordance with famed w th 0 3 Co tactin tube portions the presentinvention; which in the embodiment shown are disposed Figure 2 is atransverse sectional view of the in sup p d relation- Fillel plates 26 4generator on the line 2-2 in Figure 1; and 5) ar pr v d to p v n gasleakage Figure 3 is a sectional elevation on the line through the SideWa ls Of the furnace Where 33 in Figure 2. spaces are created betweenadjacent tube por- Figure 4 is a fragmentary plan View on a tions by theoffsetting of the tube portions 23 enlarged scale of one of the furnacecoils; from the adjacent tubes OthBI' filler plates Figure 5 is a sideview on a still further en- 30 2? r p v between contiguous u p rlargedscale of part of the coil shown in Figtions of adjacent coils, asbetween coil is and ure 4. coil M, where the lateral extension of theend In its general aspects the steam generator emportions !5, I! thereofwould otherwise leave bodying the present invention hasa U-shaped a pdue to partial p on Of the Congas passage, one leg of which forms afurnace tinuity of the helical formed wall surface.

19 downwardly fired by fuel burner means 9 In the convection pass I! thesteam generatand communicating through its inner side wall 111g surfaceis formed by ur Ve t p d at the lower end thereof with the juxtapos'i-00115 30, 3 e having u t p dtioned convection passage H f m the p r likelayers with their ultimate inlet and outlet end of hi h th spent gasespass t a Stack portions 34 and 35 connected to the horizontally :2, Thewalls of the f rnace ch ber is are disposed sections 22, 2% of theinverted L-shaped lined with radiantly heated steam generating supplyand collecting headers. Each convection surfaces comprising (as shown)three superposed 0011 -3 Comprises Sevfiral Ser es connected helicallywound tube coils !3, it and :5. Each grid-like t coils in n e p f anumof these cells is made up of a long length of ber of parallel tubesconnected by return bends small diameter tubing which is helically woundat their contiguous ends n rr d in rows to form a coil whose successiveconvolutions are tending across the ga p d located in in contact toentirely line the side walls of the a vertical pl e h row f rm n a fl rfurnace chamber, although the tube convolu- Several of which (three forp being 011- tions might be spaced apart and the intervals 50. nected inseries to form a complete convection closed by fins or otherwise. Thecoils however coil which has its ultimate end portions 34 and are notfully circular but of a roughly square 35 connected to the shorterhorizontal legs 22, shape (Fig. 2) and the inlet and outlet por- 28 ofthe inverted L-ohaped S pp d ollecttions l6, ii thereof are located atopposite coring headers respectively. The major part of more of theinner wall. These inlet and outlet each coil 30-33 is located centrallyin the convection pass I i inasmuch as the parallel tube portions of thetwo central coils SI, 32 have their contiguous end portionsinterconnected by closely coupled integral return bends 46 while thosetube portions 36, 3! which run vertically along the end i of theconvection passage and the opposite side 62 thereof forming the boundarybetween the convection passage and the adjacent furnace chamber areconnected to the contiguous tube portions by return bends or loops ofwide radius. A similar coupling arrangement is followed for the inwardlypositinned grids of the coils 3i and 33. Thus the greater number ofparallel tubes of each coil are closely spaced in the center of theconvection passage while the wider spacings of the tube portions 35 and3? from the tube portions it, il leave spaces for gas flow along thecoils in a vertical direction in the convection passage as the gases aredirected back and forth cross the convection coils by the deflectingbafiies at which extend part of the way across the convection passagefrom the end wall ll and the inner wall ti! thereof. The outermost gridportions of the two convection coils 39 and 33 being located adjacentthe side walls of the convection passage have tubes 59 thereof uniformlyspaced and provided. with fins to close the spaces therebetween andclose in the side walls of the convection passage.

The circulating pump 52 for the steam generator is supplied with waterfrom a separator drum 53 through a do-wtocomer Fi l and discharges intothe lower end of the vertically disposed portion 29 of the invertedLshaped supply header. From this vertical portion 2% of the supplyheader the water enters the end portions it of the three radiantlyheated coils l3, i i, iii and flows in parallel therethro-ugh, passingdownwardly through the helical convolutions of each coil to bedischarged from the lower ends of the three coils into the verticallydisposed portion 2i of the collecting header from which the mixture ofsteam and water flows upwardly and through the horizontal portion 23 ofthe collecting header into the and water separating drum 53.Simultaneously with the supply of water to the radiant coils iii-45 thewater passing upwardly through the vertically disposed portion 20 of thesupply header enters the horizontally disposed portion 22 thereof andfrom the latter passes through the inlet portions 34 into eachconvection coil 3al33 and in parallel through the latter. Having floweddownwardly and upwardly a plurality of times through the parallel tubeportions of each convection coil in the several parallel grid-likesections thereof the steam and water mixture is finally dischargedthrough the end portion 35 at the top of each coil into the horizontalpart 28 of the collecting header and mixing with the steam from theradiant coils l3-i5 passes into the separating drum 53.

Diametrically located on opposite sides of the vertical portions 2% and2! of the supply and collecting headers, respectively, are mountingstrips or brackets 55 to which are attached flangepcrtion E5 on theinner edges of the sides 59 of U-shaped casing sections 57, 58 foreniosing the generator.

In the event that it should become necessary to replace any part of theradiantly heated tubes in the furnace, access may be readily had to thelatter by unbolting the two side flanges 58 and casing section 58 fromthe header carriedmounting strips and then withdrawing the entire casingsection and insulation to afford direct access to the convection coils13 to l5. If necessary, any one of these may be readily removed bysimply cutting it off between the joints between its end portions [6 andI! and the nipples attached to the vertical portions 20, 2! of thesupply and collecting headers. Likewise, access may be had to theconvection section by first removing the bolts from the flanges whichconnect with the vertically disposed parts of the supply and ,collectingheaders and then drawing the section 51 and its insulation away from thegenerator so that the convection coils are exposed.

The entire radiant section including the coils 13, I4, l5 connected tothe vertical legs 20 of the headers may be removed as a unit (coils andvertical headers together with or without casing section 58 attached)upon unbolting the flanges between the vertical and horizontal headersections and also unbolting the section 57 for the convection sectionfrom the mounting strips on the headers 20, 2:. Likewise the convectionsection may be withdrawn as a unit (coils 30, 3|, 32 and headers 22, 28)upon unbolting the flanges 60 and also unfastening the radiant casing 58from the headers 20, 2!.

From the above it will be seen that the inverted L-shaped headers act asa structural support. To render this more rigid the horizontal headersections may be fastened together as indicated at 6| in Fig. 1.

Although an illustrative embodiment of the invention has been describedin detail herein there are many changes and variations that may be madewithout departing from the spirit of the invention and, therefore, it isdesired and intended to include all such changes and variations withinthe scope of the appended claims.

What I claim is:

1. Heat exchange apparatus having a furnace chamber and ajuxtapositioned convection passage connected at contiguous ends forseries flow of the products of combustion from fuel burned in thefurnace; a water supply and a steam collecting header each of L-shapedisposed respectively at opposite sides of the generator approximatelyin the plane dividing the furnace chamber and convection passage;helically wound tube coils stacked vertically in the furnace chamberwith their end portions projecting from the furnace at opposite ends ofthe wall that is common to it and said convection passage for connectionto the longer legs of said supply and collecting headers; and othersteam generating coils having opposite ends thereof connected to theshorter horizontal legs of said supply and collecting headers andmounted in said convection passage.

2. Heat exchange apparatus having a furnace chamber and ajuxtapositioned convection passage connected at contiguous ends forseries flow of the products of combustion from fuel burned in thefurnace; a water supply and a steam collecting header each of L-shapedisposed respectively at opposite sides of the generator approximatelyin the plane dividing the furnace chamber and convection passage; andhelically wound tube coils stacked vertically in the furnace chamberwith their end portions projecting from the furnace at opposite ends ofthe wall that is common to it and said convection passage for connectionto the longer legs of said supply and collecting headers; other steamgenerating coils having opposite ends thereof connected to the shorterhorizontal legs of said supply and collecting headers and dependingvertically therefrom into said convection passage and vertically spacedbaffles extending from the wall separating the furnace chamber andconvection passage and from the opposite Wall of the latter part of theway across said convection coils for directing heating gases across thelatter in a plurality of passes.

3. In a steam generator having a furnace chamber anda juxtapositionedconvection pass connected at contiguous ends to form a U-shaped passagefor series flow of the products of combustion from fuel burned in thefurnace; a water supply and a steam collecting header each of L-shapedisposed respectively at opposite sides of the generator substantiallymidway of the side Walls thereof; radiantly heated heat transfer tubeslining the furnace walls with their end portions projecting from thefurnace at opposite ends of the wall that is common to it and saidconvection pass for connection to the longer legs of said supply andcollecting headers; and other steam generating tubes disposed in saidconvection pass with coils at opposite ends thereof connected to theshorter legs of said supply and collecting headers.

4. In a forced circulation steam generator having a furnace chamber anda juxtapositioned convection pass connected at contiguous ends to forman upright U-shaped passage into one end of which fuel is introduced andfrom the other end of which products of combustion are taken off; awater supply and a steam collecting header each of inverted L-shapedisposed respectively at opposite sides of the generator substantiallymidway of the side walls thereof in the plane dividing the furnacechamber and convection passage; helically wound tube coils stackedvertically in the furnace chamber and having their end portionsprojecting from the furnace at opposite ends of the wall that is commonto it and said convection pass for connection to the longer verticallegs of said supply and collecting headers; and other steam generatingcoils spaced transversely of said convection pass with opposite terminalends thereof connected to the shorter horizontal legs of said supply andcollecting headers and depending vertically therefrom into saidconvection pass.

5. In a forced circulation steam generator having a furnace chamber anda juxtapositioned convection pass connected at contiguous ends to forman upright U-shaped passage into one end of which fuel is introduced andfrom the other end of which products of combustion are taken off; awater supply and a steam collecting header each of inverted L-shapedisposed substantially with their longer vertical legs located atopposite sides of the generator substantially midway of the side wallsthereof in the plane dividing the furnace chamber and convection passageand their shorter legs extending horizontally at the top of thegenerator; helically wound tube coils stacked vertically in the furnacechamber and having their end portions projecting from the furnace atopposite ends of the wall that is common to it and said convection passfor connection to the longer vertical legs of said supply and collectingheaders; and other steam generating coils spaced transversely of saidconvection pass with opposite terminal ends thereof connected to theshorter horizontal legs of said supply and collecting headers anddepending vertically therefrom into said convection pass.

6. Heat exchange apparatus having a furnace chamber and ajuxtapositioned convection passage connected at contiguous ends forseries flow of the products of combustion from fuel burned in thefurnace; a water supply and a steam collecting header disposedrespectively at opposite sides of the generator approximately in theplane dividing the furnace chamber and convection passage; and helicallywound tube coils stacked vertically in the furnace with their endportions connected to said headers, the superposed convolutions of saidcoils being in contact to form a continuous lining for the major part ofthe furnace wall with a number of convolutions of the coil adjacent thesaid contiguous ends of the furnace and convection passage beingstaggered on the side of the furnace adjacent the convection passage toprovide openings in the furnace wall for gas flow into said convectionpassage.

HOWARD G. NEHRBAS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

